1. Field of the Invention
The present invention pertains to an apparatus for water-granulating slag produced during smelting and/or converting operations of nonferrous metals.
2. Related Art
As is well known in the art, high-temperature slag, which may contain, as principal components, iron oxide and calcium oxide, or iron oxide and silicon dioxide, is produced in a metallurgical furnace such as a converter in the dry copper smelting process. After the separation from matte, slag of this kind is crushed into granules by bringing it into contact with a large amount of water to effect rapid quenching. This operation is, in general, called "water-granulation" or "granulation".
Japanese Patent Applications, Laid-Open Nos. H4-302993 and H4-302994, disclose conventional granulation apparatuses of the aforesaid type, which will be hereinafter explained with reference to FIGS. 1 and 2.
As depicted in FIG. 1, the conventional granulation apparatus includes a discharging launder I for discharging slag produced during smelting and/or converting operations; a receiving launder 2 arranged below the downstream end 1a of the discharging launder 1 so as to extend in a discharging direction of the slag as indicated by the arrow P in FIG. 1; and a water-jetting device 3 for jetting granulating water towards the slag, being discharged from the discharging launder 1 to the receiving launder 2. The water-jetting device 3 is constructed to have a large number of elongated water nozzles 3a (see FIG. 2), a water-supplying tubular member 3b connected to the nozzles in fluid communication therewith, and a water conduit 3c connected to the tubular member 3b at its lateral side so as to be in fluid communication therewith. The granulation apparatus further includes a burner 4 for heating a zone proximate to the discharging end 1a of the discharging launder 1 and an explosion-proof hood 5 for covering such a zone to prevent slag from being scattered in case of the occurrence of a phreatic explosion.
In the conventional apparatus as described above, a great amount of granulating water is supplied into the water nozzles 3a via the conduit 3c and the tubular member 3b. The granulating water thus supplied is jetted out from the nozzles 3a at a high jetting rate in a direction in which the receiving launder 2 extends, and contacts the high temperature slag, falling from the discharging end 1a of the discharging launder 1. Thus, the slag is rapidly quenched and crushed into granules which have a size of the order of several millimeters.
In the conventional apparatus, however, since the water nozzles 3a are of a rectangular tubular shape having a thickness t (see FIG. 2), the granulating water jelled therefrom passes a zone somewhat displaced inwardly from the inner surface of the receiving member 2, and hence it becomes difficult for the water to contact the inner surfaces of the receiving launder 2, especially the upper portions thereof. As a result, the slag contacts and adheres to the inner surfaces of the receiving launder 2 without being granulated by the water. If water contacts the lumps of slag adhering to the receiving member, phreatic explosions may occur.